用激发极化测深估算激发体深度的一个实用方法

与电阻率测深相似,激发极化测深(以下简称ВП_(вэз))也能用来确定矿体的埋藏深度。由于岩石矿物激发极化特性比较稳定,在金属矿床上用激发极化测深来确定矿体埋藏深度,比电阻率测深要优越得多。但由于目前还没有一套系统量板,而且除了几种比较简单的情况以外,理论公式的推导问题也还未全部解决。

INDUCED POLARIZATION SOUNDING,A USEFUL METHOD FOR THE DETERMINATION OF BURIED DEPTH OF ORE-BODIES

In determining the buried depth of mineral ore-bodies, the Induced polarization sounding （I.p.s.） seems more preferable to the conventional resistivity method. In view of the absence of systematic nomograms so far, and of the inability of making them under certain complicated conditions, it is discussed and analyzed in this paper the various possibilities of estimating the buried depth of ore-bodies according to the shape and characteristics of the sounding curves, on the basis of model experiment curves, theoretical curves and experimental curves from mining areas. Emphasis is laid on the relations between L. and H. (l and L correspond respectively to the 1/2 AB distance of the breaking point of the curve, and that of the point （η_k-η₁）/(η_max-η₁)=0.9, η_max here being the value for saturation. H is the depth to the top of the ore body.) various conditions are given, Ⅰ. For plane ground surface 1. slab-shaped ore body l■H, L=5-6H Roughly, these relations are independent of the volume of the ore body, its dip, and of the relative position of AB to the strike of the ore body. 2. Two-layered cross section l=1.3-1.5H, L■5-7H 3. Spherical ore body For H=0.5a-2a （a being the radius of the sphere）, l■0.75H-1.5H, L■4.5H-gH For H=a, l■H, L■6H-8H Actually, the ore bodies are slab-like, so the following may often be applied, i.e. l■H, L=5-6H Ⅱ. For rough topography 1. When the AB direction is perpendicular to the topographic strike and 1) Ore-body lying beneath a symmetric triangular mountain ridge: H≒2～2.2 （1+tanθ）/（2+tanθ）l 2) Ore-body lying beneath a symmetric triangular valley: H≒0.72l 3) Ore-body lying beneath the terrace-rim: H■2～2.2(l/1+(3/tanθ+（4+tan²θ）^1/2)) 4) Ore-body lying beneath the terrace-bend: H■l The above mentioned relations are to be further proved and corrected by laboratory studies. 2. When the sounding line is along a topographic contour, l■H is observed without any terrain condition. It is therefore proposed to lay the line along the contour, and the interpretation will be greatly simplified.